The present invention relates generally to control and status of building lighting and power systems, and more particularly to a minimizing standby power in a digital addressable lighting interface (DALI).
The demands imposed on lighting systems have changed considerably in recent years. Heretofore, switching individual or groups of luminaries on and off used to be sufficient, however, the focus for today and in the future will be on dynamic lighting. Energy conservation, more flexibility of use, increased life and reduced maintenance costs of lighting systems require lighting scene control. To create lighting scenes, luminaries generally are assigned to a plurality of groups. In addition, an end user preferably wants the option of controlling his or her luminaries. If installations having this type of flexibility are integrated into a building management system, there is also a need for simple check-back of operational status as well as global on/off control.
One method of implementing flexibility in the control of luminaries has been achieved using a new industrial standard for addressable digital lighting control called xe2x80x9cDigital Addressable Lighting Interfacexe2x80x9d or xe2x80x9cDALI.xe2x80x9d The DALI standard specifies how to control and monitor the status of individual and group addressable lighting equipment such as electronic ballasts and illumination sensors The DALI standard uses a two wire low voltage control circuit for addressing, controlling and monitoring the status of connected DALI compliant devices. The DALI standard also specifies how to determine the status of the amount of light of addressed luminaries as well as information from fire and security sensors.
DALI compliant electronic ballasts are now being manufactured which comprise all circuitry necessary to control the power to and lighting levels of a connected fluorescent lamp(s). The only connections required to these DALI compliant ballasts are power and a low voltage two wire DALI control circuit. Each DALI compliant ballast also has a unique address as well as being assignable to a group address. These control and address capabilities allow a DALI compliant lighting system to individually control the light level of each the luminaries as well as easily controlling light levels for groups of luminaries.
The DALI messages are serial data streams and comply with a bi-phase, or Manchester, coding in which the bit values xe2x80x9c1xe2x80x9d and xe2x80x9c0xe2x80x9d are presented as two different voltage levels, e.g., 16 volts and 0 volts, respectively. The coding includes error detection. A power source is provided to generate the voltage level. DALI interfaces are connected to a two wire control bus which is common to all or groups of DALI interfaces. Each DALI interface receives information by determining the voltage changes representing the bit values, and transmits information by either not clamping a voltage or clamping (shorting) the voltage across the two wire DALI control bus.
DALI messages consist of an address part and a command part (hereinafter xe2x80x9cDALI protocolxe2x80x9d). The address part determines for which DALI device the message is intended. All DALI devices may execute commands with broadcast addresses. Sixty-four unique addresses are available plus sixteen group addresses. A particular DALI device may belong to more than one group. The light level is defined in DALI messages using an 8-bit number. The value xe2x80x9c0xe2x80x9d (zero) means that the lamp is not lit. The DALI standard determines the light levels so that they comply with the logarithmic curve in which the human eye observes the light level change in a linear fashion. All DALI compliant ballasts and controllers adhere to the same logarithmic curve irrespective of their absolute minimum level. The DALI standard determines the light levels over a range of 0.1 percent to 100 percent, e.g., level 1 of the DALI standard corresponds to a light level of 0.1 percent. The DALI protocol and the DALI two wire hardware interface is unique for controlling and monitoring power devices such as lighting.
The DALI compliant ballasts and controllers do not require power when the associated lamp(s) are off. However, the DALI hardware interface requires a power source for monitoring address and control information on the DALI bus even when the associated ballast and power controller are off. Thus an independent power supply is required for each DALI hardware interface. A separate power supply for each DALI hardware interface requires space and may amount to a significant percentage of the cost of the DALI hardware interface. Also, having to continuously supply power to each DALI hardware interface amounts to a significant amount of power in a building having hundreds of light figures.
Therefore, as DALI compliant devices and lighting systems become more prevalent, what is needed is a way to minimize standby power when DALI compliant devices are inactive.
The invention overcomes the above-identified problems as well as other shortcomings and deficiencies of existing technologies by providing a system, method and apparatus for minimizing standby power in a digital addressable lighting interface (hereinafter xe2x80x9cDALIxe2x80x9d) when an associated DALI compliant device is off or inactive. Exemplary embodiments of the present invention include a DALI having a standby mode and an active mode. When in the active mode, power is supplied to the DALI by an associated power controller, and when in the standby mode, power is supplied to the DALI by a high resistance voltage dropping resistor connected to a high voltage DC source rectified from the AC line voltage power source. The power source may also be direct current (DC) in which case no rectification would be necessary. The standby power for the DALI may also be supplied by either a low power step down transformer or a high impedance voltage dropping element, e.g., a capacitor or an inductor, connected to the AC line voltage power source in combination with a rectifying diode. The DALI uses less current when in the standby mode than when in the active mode. Power is efficiently supplied from the power controller when the DALI is in the active mode, and when in the standby mode the very low current requirements of the DALI draw minimal power from the AC line voltage power source even though the voltage drop across the voltage dropping resistor is substantial. The DALI may change from the standby mode to the active mode upon detection of a DALI signal level transition on the DALI bus or at predetermined sample time intervals.
In accordance with the exemplary embodiments, the present invention is directed to an apparatus for minimizing standby power in a digital addressable lighting interface (DALI), said apparatus comprising: A power controller adapted for connection to a power source and an electrical device. A processor coupled to said power controller, wherein said processor controls the operation of said power controller, whereby when said power controller is on said processor receives power therefrom. A standby power pickup adapted for connection to the power source and connected to said processor, whereby said standby power pickup supplies power to said processor when said power controller is off. And a digital addressable lighting interface (DALI) bus interface adapted for connection to a DALI bus, said DALI bus interface is connected to said processor, wherein said processor is in a standby mode when said power controller is off and there is no signaling activity on the DALI bus, and said processor is in an active mode when said power controller is on or DALI information is detected on the DALI bus.
The DALI information is detected by said processor determining that a signal level change has occurred on the DALI bus, or said processor periodically turns on said power controller and checks the DALI bus for information.
The processor may turn on said power controller for less time than a time period between checking the DALI bus for information. The power controller may be turned on for less than 75 percent of the time period between checking the DALI bus for information. The power controller may be turned on for less than 50 percent of the time period between checking the DALI bus for information. The power controller may be turned on for less than 25 percent of the time period between checking the DALI bus for information. The power controller may be turned on for less than ten percent of the time period between checking the DALI bus for information. The power controller may be turned on for less than five percent of the time period between checking the DALI bus for information.
The standby power pickup may be a resistor, a capacitor and diode, an inductor and diode, or a step down transformer and a diode.
The power controller may include a power rectifier adapted for coupling to the power source and for rectifying. A power factor correction circuit may be used to improve the electrical device power factor. The DALI bus interface may comprise an optically isolated transmitter and receiver.
The present invention is also directed to an apparatus for minimizing standby power in a digital addressable lighting interface (DALI), said apparatus comprising: A power controller adapted for connection to a power source and an electrical device. A processor coupled to said power controller, wherein said processor controls the operation of said power controller, whereby when said power controller is on said processor receives power therefrom. A standby power pickup adapted for connection to the power source and connected to said processor, whereby said standby power pickup supplies power to said processor when said power controller is off. And a digital addressable lighting interface (DALI) bus interface adapted for connection to a DALI bus, said DALI bus interface is connected to said processor, wherein said processor is in a standby mode when said power controller is off and there is no signaling activity on the DALI bus, and said processor is in an active mode when said power controller is on or when there is signaling activity on the DALI bus.
The present invention is also directed to an apparatus for minimizing standby power in a digital addressable lighting interface (DALI), said apparatus comprising: A power controller adapted for connection to a power source and an electrical device. A processor coupled to said power controller, wherein said processor controls the operation of said power controller, whereby when said power controller is on said processor receives power therefrom. A standby power pickup adapted for connection to the power source and connected to said processor, whereby said standby power pickup supplies power to said processor when said power controller is off. And a digital addressable lighting interface (DALI) bus interface adapted for connection to a DALI bus, said DALI bus interface is connected to said processor, wherein said processor is in a standby mode when said power controller is off, and said processor is in an active mode when said power controller is on or at periodic time intervals.
The present invention is also directed to a method of operation for minimizing standby power in a digital addressable lighting interface (DALI), comprising the steps of: Providing a power controller adapted for connection to a power source and an electrical device. Controlling the operation of said power controller with a processor, wherein when said power controller is on said processor receives power therefrom. Providing power to said processor with a standby power pickup when said power controller is off, wherein said standby power pickup is adapted for connection to the power source. Providing a digital addressable lighting interface (DALI) bus interface adapted for connection to a DALI bus, said DALI bus interface being connected to said processor. And monitoring for signaling activity on the DALI bus, wherein said processor is in a standby mode when said power controller is off and there is no signaling activity on the DALI bus, and said processor is in an active mode when said power controller is on or there is signaling activity on the DALI bus.
The step of detecting signaling activity on the DALI bus is the step of determining that a signal level change has occurred on the DALI bus, or the processor periodically turning on said power controller and checking the DALI bus for information, wherein said processor turns on said power controller for less time than a time period between checking the DALI bus for information.
In addition, the present invention is directed to a system for minimizing standby power in a digital addressable lighting interface (DALI), said system comprising: A power controller connected to a power source and an electrical device. A processor coupled to said power controller, wherein said processor controls the operation of said power controller, whereby when said power controller is on said processor receives power therefrom. A standby power pickup adapted for connection to the power source and connected to said processor, whereby said standby power pickup supplies power to said processor when said power controller is off. And a digital addressable lighting interface (DALI) bus interface connected to a DALI bus, said DALI bus interface is connected to said processor, where in said processor is in a standby mode when said power controller is off and there is no signaling activity on the DALI bus, and said processor is in an active mode when said power controller is on or when there is signaling activity on the DALI bus.
The present invention is also directed to a system for minimizing standby power in a digital addressable lighting interface (DALI), said system comprising: A power controller connected to a power source and an electrical device. A processor coupled to said power controller, wherein said processor controls the operation of said power controller, whereby when said power controller is on said processor receives power therefrom. A standby power pickup connected to the power source and connected to said processor, whereby said standby power pickup supplies power to said processor when said power controller is off. And a digital addressable lighting interface (DALI) bus interface connected to a DALI bus, said DALI bus interface is connected to said processor, wherein said processor is in a standby mode when said power controller is off, and said processor is in an active mode when said power controller is on or at periodic time intervals.
The system may be used with an incandescent light, a fluorescent light, a high pressure gas electric discharge light, a low pressure gas electric discharge light, light emitting diode light and electroluminescent light. The system may also be used with a light damper on a window exposed to sunlight, remotely controllable window shades and remotely controllable window curtains. The system may also be used with a smoke detector, a fire detector, a motion detector, a light sensor, a temperature sensor and a humidity sensor. The system may further be connected to a building automation computer system.
A technical advantage of the present invention is very low power standby operation.
Another technical advantage is a cost savings in using an existing source of power from a power controller when active.
Another technical advantage is a reduction in the number of parts for a DALI.
A feature of the present invention is switching from a standby mode to an active mode when a DALI signal is detected.
Another feature is detection of the first edge of the DALI signal.
Another feature is sampling the DALI bus at a reduced duty cycle of active to is standby times.
An advantage of the present invention is reduced power usage when in a standby mode.
Another advantage is a reduction in the number of parts required.
Features and advantages of the invention will be apparent from the following description of the embodiments, given for the purpose of disclosure and taken in conjunction with the accompanying drawings.